User survey: actually collect and send the data to the backend

This switches the QTextEdit fields to QPlainTextEdit (I don't see a reason
why we should allow HTML here), no longer tries to have a default text but
instead adds labels for the two fields, connects the UI so th data is
collected and uses a bastardized WebServices subclass to send the data to
our backend.

Fixes #546

Signed-off-by: Dirk Hohndel <dirk@hohndel.org>
Fix Qt4 build

Strangely no problems on Qt5 without those declarations.

Signed-off-by: Dirk Hohndel <dirk@hohndel.org>
Merge branch 'survey'